部分体积较大的mcp安装失败率非常高

[chung1912]

有些mcp，通过npx安装的，在更新mcphub重新启动的时候，经常失败，通过NPM 仓库地址更新镜像源也不行，比如https://github.com/mongodb-js/mongodb-mcp-server或者n8n-mcp等，报错如下：

[13:32:36]error主 (499)Failed to connect client for server {
  "serverName": "n8n-mcp",
  "error": {
    "name": "McpError",
    "message": "MCP error -32000: Connection closed",
    "stack": "McpError: MCP error -32000: Connection closed\n    at McpError.fromError (file:///app/node_modules/.pnpm/@modelcontextprotocol+sdk@1.29.0_zod@3.25.76/node_modules/@modelcontextprotocol/sdk/dist/esm/types.js:2048:16)\n    at Client._onclose (file:///app/node_modules/.pnpm/@modelcontextprotocol+sdk@1.29.0_zod@3.25.76/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:263:32)\n    at _transport.onclose (file:///app/node_modules/.pnpm/@modelcontextprotocol+sdk@1.29.0_zod@3.25.76/node_modules/@modelcontextprotocol/sdk/dist/esm/shared/protocol.js:223:18)\n    at ChildProcess.<anonymous> (file:///app/node_modules/.pnpm/@modelcontextprotocol+sdk@1.29.0_zod@3.25.76/node_modules/@modelcontextprotocol/sdk/dist/esm/client/stdio.js:85:31)\n    at ChildProcess.emit (node:events:519:28)\n    at maybeClose (node:internal/child_process:1101:16)\n    at ChildProcess._handle.onexit (node:internal/child_process:304:5)\n    at Process.callbackTrampoline (node:internal/async_hooks:130:17)"
  }
}

建议增加环境变量MCP_INSTALL_PROXY可以配置http代理，然后在网页里面可以手动通过代理来安装，以解决安装失败的情况下，可以通过代理临时手动安装解决，比如以下配置：

比如，选择该按钮的时候，识别为npx命令时，适配为npx <package-name> --proxy=http://proxy:8080的方式通过代理安装；使得代理仅在本次安装时有效，不污染全局环境